Hierarchical Magnetic Films for High-Performance Plasmonic Sensors.

Hierarchically structured films comprise a growing section of the field of surface-enhanced Raman spectroscopy (SERS). Here, we report a novel, powerfully enhancing hierarchical plasmonic substrate featuring patterned multilayers of magnetic iron oxide nanospheres using an external magnetic field to create sets of radial ridges. This new substrate allows for effective analyte adsorption and significant Raman signal enhancement, thanks to the contribution of both the magnetic and plasmonic components to the electromagnetic hotspots.